Hello flashrom,
This message is most relevant to people who were reading/using the Development_Guidelines page on the old wiki website.
As of today, that old page is fully retired and redirected to new website, specifically to https://www.flashrom.org/dev_guide/development_guide.html
A section of the old page which explained to how to do the most common type of contribution, adding a new chip, now is first class document under "Contributors howtos", see here https://www.flashrom.org/contrib_howtos/how_to_add_new_chip.html
Practically this means the instructions that used to be by the links
https://wiki.flashrom.org/Development_Guidelines#Adding/reviewing_a_new_flas... or https://flashrom.org/Development_Guidelines#Adding/reviewing_a_new_flash_chi...
are now here:
https://www.flashrom.org/contrib_howtos/how_to_add_new_chip.html (even though the initial redirect will be to dev guides)